Remote control system



1945- J. H. HOMRIGHOUS 2,382,055 v REMOTE CONTROL SYSTEM Original FiledNov. 28, 1939 2 Sheets-Sheet l 25 r I R MOD. POWER ,5 7

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Aug. 14, 1945. J. H. HOMRIGHOUS REMOTE CONTROL SYSTEM Original FiledNov. 28, 1959 ,2 Sheets-Sheet P FIG8 MOTOR IN V EN TOR.

FIGIO\ Patented Aug. 14, 1945 REMOTE CONTROL SYSTEM John H. Homrighous,Oak Park, Ill.

Original application November 28, 1939, Serial No.

Divided and this application December 16, 1942, Serial No. 469,200

Claims.

My invention relates to motor control systems and more particularly to asystem for operating motors or control devices at a distance.

One of the'objects of my invention'is to provide means for transmittinga number of control signals over a single carrier to control a pluralityof motors at a distance either separately or simultaneously.

Another object of my invention is to p d means in a distant controlsystem for transmitting control characters as video signals and forreproducing these characters at the receiver to control motors or otherelectrical devices.

Another object of my invention is the provision of means for starting,stopping, and otherwise controlling at a distance motors, generators andthe like, and mobile equipment of air, land and water by televisingcertain signs or characters.

Another object of my invention is to provide means for operating a motorat a distance, from the power supply at the motor location, and atvariable speeds by transmitting signals to control the frequency ofalternating current supplied to the motor.

Various methods have been devised for controlling a motor at a distance.In one system a series of impulses are transmitted for energizing relaysto effect controls; other methods utilized different frequenciesmodulated on a carrier to effect different controls. None of thesesystems employ video signals transmitted on a single carrier to start,stop and vary the speed of a motor or to control two or more motorssimultaneously.

According to my present invention, picture signals including all controlsignals are transmitted and reproduced as picture or video sig-' rials,thereby greatly simplifying the equipment and circuits used forcontrolling one or more motors at a distance. Synchronization of thescanning operations for the cathode ray tubes are accomplished bygenerating the sweep frequencies at both the transmitter and thereceiver, and having the voltage waves at the respective line and fieldfrequencies generated at the receiver controlled by televising certaincharacters and translating these into electrical signals of properfrequencies at the receiver, and also by having the equipment forproducing the characters at the transmitter definitely locked in stepwith its generating equipment. These frequencies are applied to producethe scanning action of the pick up tube at the transmitter and thescanning action of the viewing tube, so that the electron ray in thetransmitting and receiving tubes will al- Ways be in synchronism duringthe scanning op-= oration.

This invention will be better understood by referring to the followingdescription taken in connection with the accompanying drawings in which:

Figures 1 and 2 are simplified diagrammatic views of a televisiontransmitting station and a television receiving station respectively,illustrating the principles of this invention.

Figure 3 is a motor device for generating control frequencies and forproducing certain characters for televising.

Figure 4 is an end view of one of the character forming members shown inFigure 3.

Figure 5 is an end view of disk shown in Figure 3 for generating lineand other control frequencies.

Figure 6 shows the characters for televising to synchronize the scanningoperations at the receiver with those at the transmitter.

Figure 7 shows circuits for use in my invention.

Figure 8 shows a motor driven device for generating control frequenciesat the receiver with circuits for controlling the motor from reproducedcharacters.

Figure 9 shows the control characters reproduced at the receiver.

Figure 10 shows several motor control char acters at the cathode rayreceiving tube.

In Figure 1 the numeral l designates a cathode ray transmitting tube ofconventional type, and is known as an iconoscope, and as illustrated itcomprises a mosaic, photo-electric screen on which a light image of theobject is projected and an electron gun for generating a ray ofelectrons directed at the screen, and two sets of defleeting plates fordeflecting the electron ray at I the line and field frequencies, so thatit is caused to scan the screen. The picture and certain othercharacters are thereby developed and fed by an output connector 2 to amodulating amplifier 3.

A carrier wave is provided by an oscillator 4. In the power amplifier 5this carrier wave is modulated by the frequency band video or picturesignals through the modulation amplifier 3. The signals'from theamplifier 6 are supplied by a connection 6 to the antenna I.

At the receiving station shown in Figure 2 the antenna 8 receives thecarrier signals from the transmitter antenna 1 to a radio frequency am,-plifier 9. An oscillator l0 reacts with these signals in the firstdetector stage II on the heterodyne principle to produce anintermediatedre quency which is supplied to the videointermediate-frequency stage l2.

After suitable amplification, the video signal is detected at I 3 andapplied by a connection H to a scanning device iii. The device I5 isrepresented as being in the form of a cathode-ray tube of a conventionaltype and comprises a fluorescent screen IS, an electron gun fordeveloping a ray of electrons directed at the screen, and two sets ofelectrostatic plates for deflecting the electron ray at the line andfield frequencies to cause it to scan the screen. The video signals areapplied to the control electrode of the electron gun, whereby, theintensity of the electron ray is made to vary with the video or picturesignals.

Several devices may be operated by light refiected from periodicallychanging characters appearing on the screen, such as the motors ISA,IIB, ICC and the control motor IBD for producing signals to control ortrigger the frame and line saw tooth generators HE and IBF.

Referring to Figure 3, the numeral i1 represents a motor, having anadjustable speed, which is operated from the local power circuit, andruns at approximately 900 R. P. M. I! is a drum having two black bandsi9 and each of which extends over one-half of the periphery of the drumis or through an angular distance of two fields as shown in Figure 4.The two bands are located adjacent the opposite edges of the drumrespectively, so that by rotating the drum in front of the transmittingtube two black vertical lines will appear alternately, but separated onthe mosaic, as shown in Figure 6 by the numerals 2i and 22. Thi drum l8may be known as a code sender. Thus it will be seen that each mark orsign on the mosaic will be definitely identified with a frame or picturechange, and also definitely related to the speed of the motor or 30picture change for 900 R. P. M. of the motor. These marks will bereproduced in the receiver, where they will be used to generate current,for control purposes to be further explained later. Other code sendersor drums similar to it may be employed to cause similar marks to bereproduced in the receiver.

The representation of the images shown in Figure 6, and other figureshaving similar representation, applying to the transmitting tubes, areshown similar to the way that they are reproduced for clearness. It isto be understood that the lens system of the transmitting tube willchange the image location.

The short horizontal line 23, Figure 6, shown above the vertical controlcharacters, is a permanent mark either on the mosaic of the transmittingtube 24, Figure 1, or outside the lens system of the tube at 25. Thepurpose of this short horizontal line, which is repeated in all thepictures is for automatically keeping the receivers in proper phaserelation which will be more fully explained later.

The disk 20 is mounted on the motor shaft and has four holes of equalarcs apart near its periphery'which are rotated past a source of light21, directed toward the photo-electric cell 28, which generates pulsesof current for controlling field scanning that are definitely tied inwith the speed of the motor. That is; each revolution of the motor mayproduce four fields as well as four pulses, and by the adjustment of thephoto-elec- Zric cell, these pulses are generated just at the exactinstant required. Likewise the disk 29 is rotated by the motor I]between a source of light I. and the photo-electric cell II, to generateline control pulses.

In Figure 5, I have shown another view of disk 29, divided into fourequal divisions which represent four fields, or two picture zhanges,which is easily arranged for any number of lines per field by the numberof holes in each field division of disk; also by altering the positionof the holes consecutive or progressive line scanning may be obtained aswell as interlace of 1 to 2 ratio or 1 to 4 ratio which would alsorequire reducing or increasing the number of openings in disk 28 forvertical scanning. As shown in Figure 5, field A has 220 openings andfield B has 221 openings, so positioned that the openings infield B areadvanced a distance equal to one half of the space between the holes.

From the above description, it will be seen that the pulses forcontrolling line scanning are definitely locked with the speed of themotor. Therefore any change in speed of the motor does not alter 'thenumber of openings per field or per frame.

A system or circuit for producing the proper sweep signals or saw toothvoltages is shown in Figure 7, which may be used in the receiver also asindicated at IGD and IBF Figure 2. In Figure '7, I have shown a photocell 34, which may be either cell 28 or 3| in Figure 3. This cell 3| isresponsive to the variation of light energy caused by the rotation ofthe disk 28 or 29 to cause grid excitation of amplifier tube 35. Theanode of tube 35 is connected, through a winding of transformer 36, tothe positive terminal of the voltage divider 31. The voltages induced inthe secondary winding of the transformer 30 drive the grid of tube 38positive, discharging the condenser ll through the tube. Thus byalternatively charging the condenser I9 through resistance 40 anddischarging it through the tube a saw tooth wave is generated. Thevertical sweep frequency, controlled by disk 28, is fed throughconductor II to the conductor 42 at the transmitting tube in Figure 1.The line sweep frequencies generated by disk 29 are transmitted throughconductor; 4| and 48 to the horizontal deflecting plates in thetransmitting tube.

The receiver control motor arrangement shown in Figure 8 and illustratedat IID in Figure 2, maybe provided with two disks 4! and 48 andassociated photo cells 50 and ii respectively which are exactly likethose shown in Figure 3 and need no further explanation. These disks'and tubes together with the circuits of Figure 'l illustrated at ICEand I8!" Figure 2 are for generating the sweep signals for the cathoderay receiving tube i5, Figure 2. The disks 4| and 48 are directlyconnected to the motor 52. Therefor the frequencies generated aredirectly related to the speed of the motor.

Referring to Figure 9, I have shown two frames, representing the controlsignals or marks, similar to those described in Figure 6. We will assumeto start, that the receiver is in synchronism with .the transmitter, andthat the vertical lines or characters are coming through in perfectorder. Therefore line 53 will be shown in frame 54 and line 55 will beshown in frame 56 on the television screen. Now as the picture isscanned from top to bottom and due to the direction of rotation of thewheel at the transmitter the line or mark will disappear later at thelower end than at any other portion 01' the character. Therefore rays oflight are directed from these lower mark extremities on the fiuoresencescreen 18, by the aid of a mirror the photo electric cells marks willalternate on' 51 and suitable lenses to 5B and 59. Since these thereceiving tube screen in the exact likeness as they are transmitted, analternating current may be generated in synchronism with the picturechanges.

With further reference to Figure 8, I have shown circuits for producingan alternating current from the variations of light intensitiesoccurring in the photo cells 58 and 59 which may be the same ones shownin Figure 9. These photo cells control the grid excitation of grids 66and 6| of amplifier tubes 62 and 63. The anodes 64 are connected inparallel through the primary winding of transformer 65, to the positiveside of the voltage divider 66. The cathodes 61 are connected inparallel to an intermediate point of the voltage divider. The cathode 65of photo cell 56 is connected to the grid 60 of amplifier 62 andthroughresistance 69 to negative potential at the voltage divider,thereby maintaining the grid 66 at a negative potential with respect tocathode 61 and plate 64. The circuit is so arranged, therefore, that anincrease inthe intensity of light on the photo-cell 56 will increase theplate current of tube 62. The photo-cell 59 has its anode 16 connectedto the grid 61 of amplifier tube 63, and is maintained at a positivepotential with respect to its cathode II. This causes a decrease in theplate current of tube 63, upon increasing the intensity of lightdirected toward the photo-cell 59. Other amplifier tubes may beconnected in parallel to increase the amplification. Therefore it willbe seen that the marks 53 and 55 shown in Figure 9 will alternatelyoperate the photo-cells. Explaining this more in detail, the mark orcharacter 53 in frame 54 does not reflect enough light into photo cell56 to produce any effect, but the light reflected from the location ofthe alternate mark 55 into photo-cell 59 causes a decrease in thecurrent value in tube 63. Next considering the frame 56, following frame54, the line or mark 55 occurring in the opposite location does notreflect sufficient light to the cell 59 to produce any effect. However,tube 56 will receive light from the blank space previously occupied byline 53, therefore producing an increased current at tube 62. The platecircuits of tubes 62 and 63 are connected in parallel and hence acontinuously rising and fallingcurrent is produced in the primarywinding of transformer 66, whereby alternating voltages are induced inthe secondary winding. These voltages are fed to the inverter circuitconsistin of tubes I2 and 13, each of which is provided with an anode I4and indirectly heated cathode I5 and a control electrode or grid l6. Thegrids 16 are normally biased negatively by a battery 11 through theresistance 16' and 19. The grid excitation voltage is supplied throughtransformer 65. Direct current/1's supplied through conductor 66, choke6| t mid-point of primary winding of transformer 2, thence dividedthrough the two halves of this winding to the anodes 14, a condenser 63being connected across the primary winding of transformer 62. Thecathodes 15 are connected to the source of direct current supply throughconductor 64. The secondary Winding of transformer 62 is connectedthrough the contact of the control relay 66 to the motor 52 which causesthe motor to run at the speed of the picture-changes or: in synchronismwith the motor at the transmitter, producing the control characters.

With reference to Figure 9, the short horizontal line 66 is producedfrom the permanent mark 24 or 25 at the transmitting tube and will occurin all image fields, picture changes or frames. The purpose is to giveautomatic regulation for phase control. The mark 66 is located at thetop and between the two marks 53 and 55 on the screen l6 of thereceiving tube l5. From a point, Just at left of this horizontal line66, when in proper phase relation a ray of light is directed by mirror61 and suitable lenses to a photo cell 66. This photo cell may be usedin the circuit of Figure 8 and it is sensitive to the variations oflight intensities caused by the horizontal movement of the mark 66.Should the motor 52 at the receiver get out of phase and lag behind themotor at the transmitter the line on mark 66 would move to the leftblocking light from reaching the photo cell causing it to remaininoperative, how ever, should the motor 52 get out of phase in theopposite direction or slightly increasing its speed above that of thetransmitter motor, the line 66 wouldmove to the right, causing light toenter photo cell 66 to cause grid excitation of the amplifier tube 35.The anode output of tube 35' may be applied through the transformer 89to the winding of relay 65, thereby, operating relay 65 to include theresistance 90 momentairily in the motor circuit to decrease its speed,thereby correcting the phase relation.

The operation of the receiver is as follows: the motor 52 is startedthrough the local power supply, which will produce the controlfrequencies including sweeps as have been described. The operator,through the rheostat 9| will slow the motor down, until the verticalcontrol characters 53 and 55 begin to appear on the right side of thescreen l6, in approximately the proper location vertically, whereuponthe local power supply will be shut off, and the photo electric devicewill now generate electric oscillations from the periodically changingcontrol characters on the screen to control the frequency of alternatingcurrent generated by the amplifiers I2 and 13 through the transformer 92to the input circuit of nnotor 52 which will bring the motor intosynchronism with the picture changes; the mark 66 will move to theextreme top of the picture as soon as the motor starts to operate fromthe tube supply. The line 86 may then function to adjust the horizontalscanning at the receiver in proper phase relation.

In Figure 10, I have shown three sets of characters 92, 93, and 94 inthe process of changing fields and similar in all respects to thecontrol characters 53 and 55, which may be produced at the transmitterinthe same manner described for the characters 2i and 22, except that eachset is controlled by a separate motor which may be operated separatelyand independently of each other. For instance, the set 92 may betelevised to operate at the receiver another motor ISA shown in Figure2, which may operate or control the driving motor of anaeroplane, motorcar, boat, and possibly a torpedo. Another set of characters 93 may betelevised to operate at the receiving station a third motor MB tocontrol left turn devices in the above vehicles and characters 94 may bereproduced at the receiver to operate a fourth motor I60 to controlright turn devices in the above mentioned vehicles. The characters 95may be used for synchronizing or controlling the receiver by theoperation of the control motor Figure 8 as previously explained.

The motors ISA, [6B and I6C may be operated 'from the same source ofdirect current and are similar to the motor and associated circuits ofFigure 8 except that the disk 46 and 49 would not be employed butinstead the motor shaft would drive the propelling or steering mechanismof the mobile equipment not shown. Since phase regulation would not beemployed on motors IBA, "B and "C, the motor input circuit may bebridged across resistance 90 at 96.

Thus from the above description it is to be understood that any of thedifferent sets of characters 92, 93 or M may be stopped or started atthe will of the operator at the transmitter. Furthermore, by changingthe frame scanning rate the speed of the motors at the receiver-isautomatically changed.

The embodiments of the invention which have been given herein areillustrations of how the various features may be accomplished and or theprinciples involved. It is to be understood that the invention containedherein is capable of embodiment in many other forms and adaptations,without departing from the spirit of the invention and scope of theappended claims.

This application is a division of Patent Number 2,309,393 issued Jan.26, 1943.

Having thus described my invention, I claim:

1. In a motor control system, a transmitter, means for producing aplurality of sets of different light values and for periodicallyinterchanging the light values in each set at a point within the view ofsaid transmitter, means for transmitting picture signals representativeof said sets of interchanging light values, a receiver for produclngimages from said signals in which said sets of interchanging lightvalues are reproduced along with the view, a plurality of alternatingcurrent motors at said receiver, a direct current supply circuit,apparatus and suitable circuits under the control or said sets orinterchanging light values reproduced at said receiver and coacting withsaid supply circuit to produce alternating currents to operate saidmotors.

2. The system, in accordance with claim 1, in which there is providedmeans at the transmitter for starting or stopping any one 01' the saidmotors independently of the others.

3. The method of operating a plurality of motors which comprisestransmitting from a sending station electrical signals representative ofa plurality of sets of periodically changing light values over a singletransmission path to a receiving station, translating the signals at thereceiving station into corresponding sets of periodically changing lightvalues controlling the frequency oi alternating current supplied to saidmotors in accordance with the periodically changing light values,stopping and starting any one or said m0- tors as desired by changingsaid electrical signals at the transmitting stations.

4. In a motor control system, a transmitting station, a receivingstation, means for transmitting picture signals therebetweenrepresentative of a plurality of sets of alternating image characters, aplurality of alternating current motors at said receiving station, adirect current supply circuit, apparatus and suitable circuits under thecontrol of said characters reproduced at said receiving station to enactwith said supply circuit to produce alternating currents to operate saidmotors, and means for changing said characters at the transmittingstation to stop and start any one of said motors without interferingwith the operating condition of any of the other said motors.

5. The system in accordance with claim 4 in which there is providedmeans for varying the frequency of occurrence of said characters at thetransmitter to change the speed of said motors.

JOHN H. HOMRIGHOUB.

